Croft



2 SheetsSheet 1.

(No Model.)

J. I. THORNYOROFT.

STEAM GENERATOR.

Patented May 19, 891;

YHF. News PETERS cm, Pum'wumu, WASHWGTQN, n. c.

4 (No Model.) I v 2 Sheets-Sheet 2.

J. I. THORNYGROPT.

' STEAM GENERATOR.

' No. 462,401. Patented May 19,1891.

$1.273: 65666 In 76% Z01 UNITED STATES PATENT QEEICE.

JOHN ISAAC THORNYOROFT, OF CHISIVICK, ENGLAND.

,STEAM-GENERATOR.

SPECIFICATION forming part of Letters Patent No. 452,401, dated May 19, 1891.

Application filed February 2, 1891. Serial No. 379,910. (No model.)

To all whom it Hwy concern.-

Be it known that 1, JOHN ISAAC THORNY- O ROFT, a subject of the Queen of Great Britam and Ireland, residing at Chiswick, in the county of Middlesex, England, have invented certain new and useful Improvements in Steam-Generators, of which the following is a specification' My invention relates to steam-generators of the kind wherein water is exposed to the action of heat while passing in tubes between two vessels, one of which acts as a steam collector and separatoras, for example, in the generator described in the specification of a former patent granted to me, dated August 7,1888, No. 387,547.

In order that my present improvement-s may be clearly understood, reference is had to the accompanying illustrative drawings,in which- Figure 1 shows partly in transverse section and partly in front elevation, and Fig. 2 in central longitudinal vertical section, a steamgenerator constructed according to this invention. Fig. 3 is a side elevation of the generator with a portion of the casing removed and with a part of the main water-vessel in section. Figs. 4 and 5 show in Vertical section and plan, respectively, a convenient mode of connecting the lower ends of the tubes 4* to the supplementary watervessels, which will usually be too small to permit of the tubes being fixed therein by a mandrel in the'usual manner.

1 is a horizontal steam collector and'separator.

2 is a horizontal cylindrical water-vessel,

' herein called, for distinction, the main wator-vessel.

3 3 are fire-grates arranged one at each side of the main water-vessel 2.

2 2 are supplementary water-vessels arranged at the outer sides of the fire-grates and each in communication with the main water-vessel.

4 4 are two series of bent tubes connecting the main water-vessel 2 with the upper part of the steam collector and separator.

4* 1* are two series of bent tubes connecting the supplementary water-vessels 2 with the upper part of the steam collector'and separator, and 5 5 are return-tubes connecting 6 between them, that extends the whole length of the generator and communicates at one end with a chimney 7. The smoke-box is bounded by the tubes 4:, the under side of the steam collector and separator 1, and the top of themain water-vessel 2, and through it the return-tubes 5 pass, as shown.

. S 8 are bent plates extending longitudinally through the smoke-box, so as to divide the same into three partsviz., two outer ones that serve for the passage of the hot gases to the chimney and an intermediate one in which are located the return-tubes 5. By this construction the return-tubes are protected from direct contact with the hot gases, and the downward flow of water through them is thereby facilitated.

The two series of tubes marked, collectively, 4:, Fig. 1, are so bent and arranged that some of the tubes of each series are arranged close together for the greater part of their length to form inner and outer longitudinal tubulous close walls A and B, respectively, of a flue O and are bent at other parts to form inlet and-outlet spaces 0 and 10, as described in my said former specification, and within each flue thus formed the remaining pipes of the series are arranged either separately, as described in the said former specification, or so that the pipes of every two rows are made to form a single longitudinal row of pipes except near their ends, as shown in Fig. l.

The plates 8 serve, in addition to protecting the return-tubes 5, to prevent the direct escape of hot gases from the fines G into the smoke-box 6 through the spaces between the lower ends of the tubes 41, forming the inner walls B of the flues. Each series of bent tubes at consists at the extremities,where connected to the steam collector and separator l and supplementary water-vessel 2, of two 7 rows, whose intermediate portions merge into one row that constitutes a wall of closely-arranged tubes.

In the example shown each supplementary water-vessel 2 is formed with a bend 2 and is in connection therethrough with the main water-vessel 2, as indicated in Figs. 1, 2, and

ICC

a. The wall of tubes T15 extends along the bcntportion of the supplementary water-Yessel, as represented. Each series of tubes l is arranged to touch the tubular wall A otthe adjacent series of tubes at A*, so as to practically close the top of the lire-box. Flame and hot gases pass from each tire-box through the spaces 9 at the bottom of the wall A of tubes into the corresponding tlue C, and thence escape through the spaces 10 at the top of the inner wall B of tubes into the smoke-box t3 and chimney 7. The front ends of the tire-boxes and those parts of the rear ends not closed by the tubes i are closed, except opposite the tire-doors, by fire-brick.

11 11 are metal casings inelosing the tubes 4 and 4* and the front of the generator.

\Vith the above-described arrangement the principal groups of tnbes--viz., the groups -.t lare located between two tires, there being only one wall of tubesviz., t*at eachouter side, so that there shall not be liability to any of the rows of tubes being cooled and the circulation therein being thus stopped or impaired. Furthermore, by causing the hot gases to escape from the tines G into the smoke box 6 through the spaces 10 at the upper end of the inner wall B of tubes, instead of through the outer wall, as heretofore, they are made to pass between the tubes near to the water-level in the steam collector and separator, and thus the upper parts of the tubes will not be liable to overheating. The arrangement, moreover, by utilizing the space inelosed by the tubes & at each side of the lower part of the steam collector and separator as a smoke box or boxes for collecting the gases on their way to the chimney, improves the evaporative ellieieney and at the same time enables a generator of a given power to be placed under coal-bunkers or in other situations where the height available is limited and would not aecommodate a generator of the same power and similar class as heretofore usually constructed.

In the above described construction of steam-generator it is advantageous to make the tubes 4 of a simple curved form, consisting, to a large extent, of one bend of constant radius, and with straight ends simply, but slightly bent at the extremities to adapt them to lit the varying angles of the holes in the steam collector and separator and the main water-vessel, thus tending to reduce cost. It will usually be advantageous to impart a bended form to the return-tubes 5, as shown in Figs. 2 and 3, to allow for change of form of the steam collector and separator and the main water-vessel, due to local heating of these parts, and then in some cases they may be simply secured by a mandrel or tube-expander. The chimney 7 may be attached to the fire-door end of the boiler or to the opposite end, as in the example shown. Large boilers mightbe adapted to be fired at both ends in a manner that will be readily understood without drawings.

The steam collector and separator is provided with any suitable arrangement of battle plate or platcs-for example, the plates 12- against which jets of mixed water and steam are poured from the upper ends of the tubes a and 4* when the generator is at work, the water falling to the lower part of the steam collector and separator, and thence through the return-tubes 5 and water-vessels 2 and 2 to the tubes l 45*", wherein it is turtherheatcd. The steam passes under the lower edges of the battle plate or plates and enters a perforated steam-pipe 1 3, whence it can be conducted away for use.

Suitable constructions of battle-plates are described and shown in my said former specitication and in an application for patent tiled by me, dated October 27, 1800, Serial No. 369,526.

14 is a pipe for supplying feed-water, which it is advantageous to admit to the steam collector and separator in order to aid the descent of water through the return-tubes 5. To this end, also, the feed-pipe is perforated at its under side and arranged to extend longitudinally within the steam collector and separator, so as to cause the feed-water to be distributed as uniformly as practicable to the several tubes.

The lower ends of the tubes .4 may advantageously be secured to the small supplementary water-vessels 2 by a union of the construction shown in Figs. 4: and 5, and comprising a socket 15, formed with internal screw-thread 17 and with an externally-screwthreaded tubular part 10, screwed into the wall of the steam collector and separator and water-vessel, as the case may be.

18 is a gland screwed into the socket 15, between which and the inner end 01' the gland the flange 19 of the tube it or 45 is firmly held steam-tight.

\Vhat I claim is 1. In a steam-generator, the combination of a steam collector and separator, a main watervessel in communication therewith, a supplementary water-vessel in com munieation with said main water-vessel, and bent tubes eonnecting each of said water-vessels with the top of said steam collector and separator and arranged to form the top and sides of a tirebox, the tubes forming one side of said tirebox being arranged to form a tubulous wall, and some of the other tubes being arranged close together for the greater portion of their length to form inner and outer longitudinal tubulous close walls of a line, within which the remainder of said tubes are arranged, and bent at other parts to form inlet and outlet passages for hot gases to and from said flue, substantially as herein described.

2. In a steam-generator, the combination of an upper steam collector and separator, lower main and supplementary watervessels in communication therewith, and bent tubes connecting the said water-vessels with the top of said steam collector and separator, said ICC tubes being arranged in four series, so as to form two fire-boxes, between which the principal groups of tubes are located, substantially as herein described.

3. In a steam-generator, the combination of a steam collector and separator, a main water-vessel in communication therewith, sup-' plementary water-vessels in communication with said main water-vessel, and bent tubes connecting each of said water-vessels with the upper part of said steam collector and separator and arranged to form two fireboxes and an intermediate smoke-box.

4:. In a steam-generator, the combination of a steam collector and separator, a water-vessel in communication therewith, and two series of bent tubes arranged to connect said water-vessel to the upper part of said steam collector and separator and to form in conjunction with said steam collector and separator and water-vessel a smoke-box, some of said tubes of each series being arranged close together for the greater part of their length to form inner and outer longitudinal close tubulous walls of flues, within which the other tubes of the series are placed, and the tubes forming said outer wall being bent at their lower ends to form inlets to the bottom of said flue, and the tubes forming said inner wall being bent at their upper ends to form outlets from the top of said flue into said smoke-box, substantially as herein described.

5. Ina steam-generator, the combination of a steam collector and separator, a main water-vessel in communication therewith, supplementary water-vessels in communication with said main water-vessel, two fire-grates,

one at each side of the main water-vessel, two

series of bent tubes connecting the main water-vessel with the upper part of said steam collector and separator and arranged to form between them a smoke boX or boxes, and two series of bent tubes connecting the supple mentary water-vessels t0 the upper part of the said steam collector and separator, the tubes in each of these latter series being arranged to form a tubulous outer wall for one of said fire-boxes, substantially as herein described.

6. In a steamgenerator, the combination of a steam collector and separator, a main Water-vessel, supplementary water-vessels in communication with said main water-Vessel, bent tubes connecting each of said water-vessels with the top of said steam collector and separator and arranged to form the sides and top of two fire-boxes and an intermediate smoke-box. and return-tubes connecting said steam collector and separator with said main water -'vessel and extending downward through said smoke-box, substantially as herein described.

'7. In a steam-generator, the combination of a steam collector and separator, a main water-vessel, supplementary water-vessels in communication with said main water-vessel, bent tubes connecting each of said water-Vessels with the top of .said steam collector and separator and arranged to form the sides and top of two fire-boxes and an intermediate smoke-box, plates arranged longitudinally within said smoke-box, so as to divide the same into a'central chamber and two outer passages, and return-tubes connecting said steam collector and separator with said main water-vessel and extending downward through the central portion of said smokeboX, substantially as herein described, for the purposes specified.

8. In a steam-generator, the combination of a steam collector and separator 1, a main water-vessel 2, bent return-tubes 5, connecting the two, fire-grates 3, supplementary watervessels 2, located at the outer sides of said fire-grates and connected to said main watervessel, tubes 4 and 4*, connecting the said water-vessels 2 and 2 with the top of said steam collector and separator, some of said tubes 4 being arranged to form fiues within which other of said tubes are located and having inlets 9 at the bottom and outlets 10 at the top, and said tubes 4* being arranged to form a single tubulous wall at theouter side of each fire-box, a smoke-box formed by and between said tubes 4, steam collector and separator 1, and main water-vessel, and bent plates arranged longitudinally within said smoke-box,so as to divide the same into three parts, within the inner of which said tubes 5 are located, substantially as herein described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

JOHN ISAAC THORNYCROFT.

Witnesses:

WM. THos. MARsHALL, H. O ARLIER, Both of 2 Popcs Head Alley, Oo'rnhfll, London, Gentlemen. 

